Pancake is another standard test problem of cosmological hydrodynamics simulation [1]}. We have run the collapse of a one-dimension pancake in a purely baryonic universe with \(\Omega =1\)  and \(h=\frac{1}{2}\) . Initially, at \(a_{i}=1\) , which corresponds to \(z_{i}=20\)  in this test, a sinusoidal velocity field with the peak value \(0.65/(1+z_{i})\)  in the normalized unit has been imposed in a box with the comoving size \(64h^{-1}Mpc\) , so that the shock forms at \(z=1\) . The initial baryonic density and pressure have been set to be uniform with \(\rho =1\)  and \(p=6.2\times 10^{-8}\)  in the normalized code units. We applied initial uniform magnetic fields \(B_y = 2.0 \times 10^{-5}G,~B_x=B_z=0\)  in the simulation. We did the calculations with unigrid with 1024 cells and AMR run with 256 cells of root grid and 2 level refinements. Figure REF  shows the density and \(B_y\)  at \(z=0\) .
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